This invention relates to a catch basin erosion containment filter assembly.
Water runoff from construction sites may find its way into the catch basin of a storm water sewer system. Such water may be contaminated with mud and debris generated by construction or other activities, and may also be contaminated with oil or fuel.
It is highly desirable that such contaminants be prevented from entering the sewer system.
It is known to place bags filled with bark and chips in front of the catch basin to capture such contaminants.
It has also been suggested to place a filter material on top of or beneath the grate covering the catch basin.
It is an object of this invention to provide a filter assembly that can be inserted into the catch basin at the entrance thereof to capture sedimentary contaminants entering with the water runoff.
It is a further object to provide a filter structure that can also capture hydrocarbon contaminants such as fuel and/or oil entering with the water runoff.
The filter assembly of this invention is comprised of a frame and a containment bag attached to the frame at its open end. Although the containment bag can be formed of a single layer of material, it is preferred that the containment bag be a laminate having at least two layers, the outer layer having a higher porosity and higher strength than the inner layer.
The outer layer is preferably a woven geotextile. The inner layer is preferably a nonwoven geotextile.
The laminate of the filter structure may have a fuel/oil absorbent intermediate layer. The intermediate layer is preferably a melt blown polyolefin such as polypropylene.